Well logging method and apparatus



y 1951 HENRI-GEORGES DOLL 2,554,174

WELL LOGGING METHOD AND APPARATUS Original Filed June 13, 1942 3Sheets-Sheet 3.

SOURCE OF ELECTRICAL ENERGY REfiORDER INVENTOR. HENRI-GEORGES sou.

H IS AT TORNEYS.

May 22, 1951 HENRFGEORGES DOLL WELL LOGGING METHOD AND APPARATUSOriginal Filed June 15. 1942 3 Sheets-Sheet 2 v sNvENToR.

HENRIGEORGES DOLL 5%EIATTCRNEYS y 195l HENRI-GEORGES DOLL 2,554,174

WELL. LOGGING METHOD AND APPARATUS 3 Sheets-Sheet 3 Original Filed June13, 1942 84 FIG. 5.

RECORDE RECTIFIER 33 FIG. 4.

h INVENTOR.

HENRI-GEORGES DOLL HIS ATTORNEYS.

Patented May 22, 1951 WELL LOGGING METHOD AND APPARATUS Henri-GeorgesDoll, Houston, Tex., assignor to Schlumberger Well SurveyingCorporation, Houston, Tex., a corporation of Delaware Originalapplication June 13, 1942, Serial No.

446,888. Divided and this 8, 1947, Serial No. 778,683

application October 8 Claims. (Cl. 175182) The present invention relatesto methods and apparatus for investigating earth formations traversed bya bore hole, and more particularly to a new and improved method andapparatus for determining the depth and thickness of permeableformations traversed by a bore hole.

This application is a division ofmy copending application Serial No.446,888, filed June 13, 1942, for Method and Apparatus for InvestigatingEarth Formations Traversed by a Bore Hole, now Patent No. 2,433,746,granted December 30, 1947.

The above mentioned copending application discloses that alternatingelectrofiltration po tentials can be created by producing periodicpressure fluctuations in the bore hole liquid in the vicinity ofpermeable formations, which alternating potentials may be availed of inlocating permeable formations. The basic theory is fully set forth inthat application and will not be repeated herein.

The present application is addressed to methods and apparatus of theabove character in which the periodic pressure fluctuations are producedby directing a jet or jets of liquid into the bore hole liquid.

The invention may be better understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

Fig. l is a schematic diagram in longitudinal section of apparatusconstructed according to the invention for producing periodicallyvariable potentials related to electrofiltration potentials in a borehole;

Fig. 2 illustrates a curve of electrofiltration potentials such as mightbe obtained by means of the apparatus shown in Fig. 1;

Fig. 3 is a schematic diagram in longitudinal section of a furthermodification of the invention utilizing a liquid operated turbine in thebore hole for producing pressure variations therein;

Fig. 3a is a View in section taken along line 3a-3a of Fig. 3 andlooking in the direction of the arrows;

Figs. 3b and 3c are sectional views of portions of the apparatus shownin Fig. 3, taken along lines 3b-3b and 3.c 3c, respectively, and lookingin the direction of the arrows;

Fig. 4 shows the apparatus of Fig. 3 in position in a bore hole andillustrates schematically the electrical connections employed; and

Fig. 5 shows an illustrative curve which might be obtained with theapparatus of Figs. 3 and 4.

Referring to Fig. 1, the apparatus I0 comprises a casing 5| suspended ona conventional type bail 52 secured to the supporting cable 21 in thebore hole l2 which contains a column of liquid l l. Mounted in the upperportion of the casing 5| is a downwardly extending conduit 53 having alarge mouth 54. The conduit 53 converges downwardly and divides into twooppositely directed conduits 55 and 56 located in the lower portion ofthe casing 51.

At the junction of the conduits 55 and 56 is mounted a conventional typeclapper valve 51 which is adapted to be moved periodically from theposition shown in full lines to the position shown in dotted lines inthe drawing. This may be accomplished in any suitable manner, as, forexample, by mounting an arm 553 having a longitudinal slot 59 therein onthe shaft of the clapper valve 5'5. Within the slot 59 is adapted to bereceived a pin 68 secured on a rotatable disc 61 driven by aconventional type electric motor 62. One terminal of the motor 62 isconnected to the conductor 26 in the supporting cable and its otherterminal is grounded to the casing 5! at the point 63. The cableconductor 26 may be connected in series with a switch 28 to one terminalof a suitable source of electrical energy 29, located at the surface ofthe earth, the other terminal of which may be grounded at 30.

In operation, the switch 28 is closed at the surface of the earth,supplying electrical energy from the source 29 to the electric motor 62.The disc 6| begins to rotate and moves the clapper valve 51 periodicallyfrom the position shown in heavy lines to that shown in dotted lines.Meanwhile, the casing 5| is moved upwardly through the bore hole byapplying tension to the supporting cable 21 so that the bore hole fluidl l is directed through the conduit 53 and alternately through theconduits 55 and 56.

The jetting action of the bore hole fluid ll produced in its passagethrough the diametrically opposite conduits 55 and 56 produces avigorous lateral vibration of the casing 5| and alternately compressesthe bore hole liquid l I in the vicinity of the outlets of the conduits55 and 56. As described above, the periodic variation in the pressure ofthe bore hole liquid II is accompanied by corresponding variations inthe electrofiltration potentials existing in the vicinity of permeableformations.

These potential variations may be picked up, for example, by measuringthe potential difference between two insulated electrodes 64 and 65located on opposite sides of the casing 5| in the vicinity of theconduits 55 and 56. The

electrodes 64 and 65 may be connected to the conductors 33 and 49 in thesupporting cable and the potential differences picked up are measured bythe recording apparatus 34 at the surface of the earth.

A representative curve, such as might be obtained with the apparatusshown in Fig. 1, is illustrated in Fig. 2 of the drawings. As shown inthis figure, the curve of spontaneous potentials at the level ofrelatively permeable formations has approximately a sinusoidal shape andits frequency is the same as the frequency of vibration of the apparatusin the bore hole.

In the embodiment illustrated in Fig. 3 of the drawings, a hydraulicturbine is employed to produce periodic variations in the pressure ofthe bore hole liquid at different depths in the bore hole. Referring toFig. 3, the apparatus comprises a casing 66 at the upper extremity ofwhich are mounted a plurality of flexible fins 61 which serve tomaintain the casing 66 in fixed relation to the axis of the bore holeI2. Although any desired number of fins 61 may be used, preferably fourare provided, which are disposed 90 apart, as shown in greater detail inFig. 3a, and they may be made of any suitable resilient material, suchas rubber or neoprene, for example.

Secured to the lower portions of the flexible fins 61 are a plurality offlaps 68 made of any suitable material, such as canvas, for example,which extend between the outer edges of adjacent fins 61, as shown, toform a funnel for directing the bore hole liquid II to a plurality offluid inlets 69 formed in the casing 66. It will be noted that when thecasing 66 is lowered into the bore hole I2 the canvas flaps 68 will becollapsed by the movement of the casing 66 through the bore hole liquidII. On the other hand, when the casing 66 is raised in the bore hole thefiaps 68 will be expanded into the operative position, forming a largefunnel as shown in the drawings.

The fiuid inlets 69 in the casing 66 communicate with a chamber I0,which in turn communicates with the inlet port II of a conventional typehydraulic turbine I2. The turbine I2 comprises two sets of stator blades13 and I4 between which is rotatably mounted a rotor I5 having aplurality of blades I6 mounted thereon.

In order to provide for periodic pressure variations in the bore holeliquid I I, a bottom closure member I1 is provided between two adjacentblades I6 on the turbine rotor I5, as shown in greater detail in Fig.3b. Also, similar bottom closure members I8 and 18a are provided be-Ji-L' tween two pairs of adjacent fixed blades I4 below the rotor andoutlets 80 and 89a are formed directly opposite the two pairs ofadjacent blades I4 which have been so closed off.

While the device will function with only one outlet 80, it is preferableto provide two in order to increase the vibrational energy imparted tothe bore hole liquid. It is also desirable to have one or more lessblades on the rotor I5 than there are stator blades I4. With thisconstruction, the closure member 11 on the rotor I5 subtends a greaterare than the passages between the blades 14 to which the bottom closuremembers 18 and 18a are secured, and reduces to a minimum any leakagefrom the outlets 853 and 80a when the rotor bottom closure member TIlies over the stator blades I4 to which the closure members I8 and 18aare secured.

In operation, the casing 66 is lowered to the bottom of the bore hole onthe supporting cable 21 (Fig. 4). While it is being lowered, the flaps68 between the fins 61 are collapsed so that they do not impede themovement of the apparatus in the bore hole. The apparatus is thenraised, whereupon the flaps 68 expand to form a funnel, as shown in thefigure. This funnel directs the bore hole liquid II through the fiuidinlet 69 and the chamber 10 to the turbine inlet I I, causing the rotorI5 thereof to rotate at a speed which depends upon the speed at whichthe apparatus is moved through the bore hole I2.

So long as the bottom closure member I? between the two rotor blades IBis not directly over either of the two pairs of adjacent blades M towhich the bottom closure members 76 and 78a are secured, water will passthrough the turbine I2 and through the outlets 8i) and 86a from which itwill be jetted radially against the wall of the bore hole I2. The waterwill also be continu ously exhausted through the turbine outlets 8|.However, when the bottom closure I1 moves directly over either of thetwo pairs of adjacent blades I4 to which the bottom closures I8 and 18aare secured, practically no fiuid will pass through the correspondingopening 33 or 62a but substantially all the fluid will pass through theother opening and the turbine outlet BI. Accordingly, as the rotor I5rotates, intermittent and alternate jets of water will be directed fromthe outlets S0 and 80a, thereby producing a lateral vibration of thecasing 66 and periodically varying the pressure of the bore hole liquidII at the level of the apparatus in the bore hole.

The variations in the electrofiltration potential produced by theperiodic variations in the pressure of the bore hole liquid I I may bepicked up by a pair of insulated electrodes 82 and 83 located onopposite sides of the casing 66 near the outlets 80 and 80a. Theelectrodes 82 and 83 may be connected to the conductors 33 and 19 in thesupporting cable 21 (Fig. 4) to a conventional type rectifier 84 at thesurface of the earth, the direct current output of which is impressedupon the recording apparatus 34. The rectifier 84 serves to rectify theperiodically varying electrofiltration potential which is produced inthe bore hole I2, so that the curve recorded has substantially the shapeshown in Fig. 5 of the drawings.

Where a single outlet 80 is employed, the pressure variations producedmight be augmented by providing a similar closure member for anotherpair of adjacent rotor blades 16, preferably at a position diametricallyopposite the closure member 'I'I, increasing the number of rotor blades16. if necessary, to do this. This would, of course, double thefrequency of vibration of the apparatus.

Inasmuch as the periodic pressure changes in the modification describedabove are produced and controlled by mechanical and hydraulic means,there are no current carrying conductors in the supporting cable 21other than the conductors 33 and 49, which transmit theelectrofiltration potentials to the surface of the earth. Accordingly,the electrofiltration potentials picked up may be very accuratelymeasured.

The alternating electrofiltration potentials may be measured in otherways than those shown above. For example, the recorder 34 might beconnected to one electrode located substantially at the level of theapparatus in the well and a reference electrode located either a shortdistance away or at the surface of the earth. As a further modification,indications might be obtainedof the voltages between each of the twoelectrodes in Figs. 1 and 3 and ground.

The invention thus provides a new and improved method and apparatus forobtaining indications of electrofiltration potentials apart from othercontinuous potentials that may be present in a bore hole. By producing alocalized and periodically variable pressure variation at differentdepths in the bore hole, continuous electrofiltration potentials may bechanged to alternating potentials that can be readily separated fromother continuous potentials which may be encountered. Accordingly, theinvention enables accurate indications of electrofiltration potentialsto be obtained without taking any special precautions even in wellslocated in the vicinity of relatively strong telluric currents.

The several embodiments described above are intended to be illustrativeand not restrictive. Numerous modifications in form and detail may bemade in those embodiments Within the scope of the following claims.

I claim:

1. A method of investigating earth formations traversed by a bore holecontaining a column of liquid, comprising lowering into the bore hole abody having fluid outlet means therein, periodically directing a jet offluid from said oulet means into the bore hole liquid at differentdepths in the bore hole, thereby creating periodically varyingelectrofiltration potentials in the vicinity of permeable formations,and obtaining indications of said varying potentials between a point inthe vicinity of said jet of fluid and a point at a reference potential.

2. A method of investigating earth formations traversed by a bore holecontaining a column of liquid, comprising lowering into the bore hole abody having a plurality of spaced apart outlets therein, periodicallyand alternately directing jets of fluid from said outlets in differentdirec tions into the bore hole liquid at different depths in theborehole, thereby creating periodically varying electrofiltrationpotentials in the vicinity of permeable formations, and obtainingindications of said varying potentials between a point in the vicinityof said jet of fluid and a point at a reference potential.

3. Apparatus for investigating earth formations traversed by a bore holecontaining a column of liquid, comprising a body adapted to be loweredinto a well and having outlet means therein, means for periodicallydirecting a jet of fluid from said outlet means into the bore holeliquid at different depths in the bore hole, thereby creatingperiodically varying electrofiltration potentials in the vicinity ofpermeable formations, and means for obtaining indications of saidvarying potentials between a point in the vicinity of said jet of fluidand a point at a reference potential.

4. Apparatus for investigating earth formations traversed by a bore holecontaining a column of liquid, comprising a body adapted to be loweredinto a bore hole and having spaced apart outlets formed therein, meansfor periodically and alternately directing jets of fluid from said bodyoutlets into the liquid at different depths in the bore hole, therebycreating periodically varying electrofiltration potentials in thevicinity of permeable formations, and means for obtaining indications ofsaid varying potentials between a point in the vicinity of one of saidjets and a point at a reference potential.

5. Apparatus for investigating earth formations traversed by a bore holecontaining a column of liquid, comprising, a casing having a mouth atthe upper end thereof, said mouth converging downwardly and dividinginto at least two laterally extending conduits, means for alternatelyblocking the passage of fluid through said conduits, an electrodeassociated with said casing and movable therewith, and means forexhibiting a function of alternating potentials existing between saidelectrode and a ground point.

6. Apparatus for producing periodic variations in the pressure of theliquid contained in a bore hole drilled into the earth, comprising, acasing adapted to be lowered into a bore hole, a fluid driven turbine inthe casing, said turbine having rotor blades and stator blades, meansfor directing bore hole liquid to the turbine, means for blocking thepassage of fluid between two adjacent rotor blades, means for blockingthe passage of fluid between two adjacent stator blades, and an outletin the casing communicating with the space between said last named twostator blades.

'7. Apparatus for investigating earth formations traversed by a borehole containing a column of liquid, comprising, a casing adapted to belowered into a bore hole, a fluid turbine in the casing, said turbinehaving stator blades and rotor blades, means for blocking the passage offluid between two adjacent rotor blades, means for blocking the passageof fluid between two adjacent stator blades, an outlet in the casing,communicating with the space between said last named two stator blades,means for directing fluid to the turbine when the casing is raisedthrough the bore hole, an electrode associated with the casing andmovable therewith, and means for exhibiting a function of alternatingpotential differences between said electrode and a point of reference.

8. A method of investigating earth formations traversed by a bore holecontaining a column of liquid, comprising lowering into the bore hole abody having spaced apart outlets therein, periodically and alternatelydirecting jets of fluid from said outlets in dilferent directions intothe bore hole liquid at different depths in the bore hole, therebycreating periodically varying electrofiltration potentials in thevicinity of permeable formations, and obtaining indications of saidvarying potentials between spaced part points in the vicinities of saidjets, respectively.

HENRI-GEORGES DOLL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,190,686 Slichter Feb. 20, 19402,214,786 Bishop Sept. 17, 1940 2,249,769 Leonardon July 22, 19412,313,384 Lee Mar. 9, 1943 2,364,957 Douglas Dec. 12, 1944

